PHYSICS · Multi-part · CBSE · Physics · Current Electricity · Current Electricity
Problem
Metallurgical students are often told that, for a given material and length, the resistance of a wire increases rapidly as its diameter is reduced.
(i) Derive a mathematical expression to show that the resistance of a uniform cylindrical wire is inversely proportional to the square of its diameter for fixed length and material.
(ii) Explain the physical meaning of this result and state two practical consequences of this relation when designing high-value resistors using metallic wire.